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Power distribution network grounding fault single-interval comprehensive protection method

A ground fault and comprehensive protection technology, which is applied in the direction of protection that responds to fault currents, emergency protection circuit devices, and emergency protection devices that automatically disconnect, can solve problems such as difficult to quickly process ground faults, and achieve high-sensitivity grounding Effects of fault detection function, simplified protection configuration, and faster fault handling

Active Publication Date: 2021-01-22
NR ENG CO LTD +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a single-bay comprehensive protection method for distribution network grounding faults, which solves the problem that it is difficult to quickly process various types of grounding faults under different grounding methods when only single-bay protection devices are configured.

Method used

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  • Power distribution network grounding fault single-interval comprehensive protection method
  • Power distribution network grounding fault single-interval comprehensive protection method
  • Power distribution network grounding fault single-interval comprehensive protection method

Examples

Experimental program
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Embodiment 1

[0031] In this embodiment, the connection of the distribution network grounding fault single-bay comprehensive protection system is realized as follows: figure 1 As shown, the ground fault single-bay comprehensive protection device is connected to the bus three-phase voltage transformer and the zero-sequence current transformer in this bay to complete the acquisition of the bus three-phase voltage and the zero-sequence current in this bay; according to the collected bus voltage and zero-sequence current transformer Sequence current judges the existence of ground fault, judges the fault in the area and cuts off the fault.

[0032] Embodiment 1 of a comprehensive protection method for distribution network grounding fault single interval includes the following steps:

[0033] Step 1: Sampling with dual frequency in real time, in which the low-frequency frequency is greater than 100Hz and the high-frequency frequency is greater than 6000Hz, and the three-phase voltage and zero-seq...

Embodiment 2

[0042] Embodiment 2 of a single-bay comprehensive protection method for ground faults in distribution networks. The ground fault single-bay comprehensive protection device is connected to the bus three-phase voltage transformer and the zero-sequence current transformer in this bay, and is used to complete the bus three-phase voltage, Collect the zero-sequence current at this interval; judge the existence of ground faults, judge the faults in the area and remove the faults according to the collected bus voltage and zero-sequence current.

[0043] In this embodiment, the primary value of the voltage transformer is 10kV, the secondary rated value is 100V, and the transformation ratio of the branch zero-sequence transformer is 50 / 1, so the fixed value of the zero-sequence voltage U 0set Set to 15V, zero-sequence voltage mutation ΔU 0set Set to 5V, zero-sequence overcurrent setting I 0set It is set to 0.1A, and the fixed values ​​are all quadratic values.

[0044] Ground fault de...

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Abstract

The invention discloses a power distribution network grounding fault single-interval comprehensive protection method. Double-frequency sampling is adopted, a low-frequency sampling signal is used fordetecting a single-phase grounding fault and a single-interval conventional protection function of a large-current grounding system, and a high-frequency sampling signal is subjected to wavelet packettransformation to detect a single-phase grounding fault of a small-current grounding system. The grounding mode of the system is adaptively detected, and a corresponding criterion is selected to perform single-phase grounding judgment. The method can be implemented in a conventional single-interval comprehensive protection device, solves the problem that various types of grounding faults are difficult to process quickly in different grounding modes when only a single-interval protection device is configured at present, and does not need to configure a centralized small-current grounding lineselection device, the problem that an existing centralized small-current grounding line selection device is complex in wiring can be solved, protection configuration is effectively simplified, and theinvestment is saved.

Description

technical field [0001] The invention relates to the field of relay protection of electric power systems, in particular to a comprehensive protection method for distribution network ground fault single interval. Background technique [0002] In the 3kV-66kV power system, single-phase grounding is a relatively common fault type. [0003] For large-current grounding systems, the steady-state zero-sequence overcurrent method is generally used to detect grounding faults. When a grounding fault occurs on a line, it is mostly not an instantaneous metallic grounding, but a transition resistance exists at the grounding point, especially a large transition resistance, so that the grounding current is very small and cannot reach the action value of the zero-sequence overcurrent protection, which often causes protection failure. Refuse to move. [0004] For the small current grounding system, when single-phase grounding occurs, the grounding fault current is very small, and the steady...

Claims

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Application Information

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IPC IPC(8): H02H3/16H02H1/00
CPCH02H3/165H02H1/0007Y04S10/52
Inventor 王勇房光华李磊李乃永刘晓亮赵健龙石勇房俏侯炜李玉敦高金伟陈俊李天舒徐舒范荣奇李靖姜淼戈宁黄海丽李国强卢晓惠曹凯
Owner NR ENG CO LTD
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